This is a patch that implements a generic hooking API for the generic ACPI battery driver. With this new generic API, drivers can expose platform specific behaviour via sysfs attributes in /sys/class/power_supply/BATn/ in a generic way. A perfect example of the need for this API are Lenovo ThinkPads. Lenovo ThinkPads have a ACPI extension that allows the setting of start and stop charge thresholds in the EC and battery firmware via ACPI. The thinkpad_acpi module can use this API to expose sysfs attributes that it controls inside the ACPI battery driver sysfs tree, under /sys/class/power_supply/BATN/. The file drivers/acpi/battery.h has been moved to include/acpi/battery.h and the includes inside ac.c, sbs.c, and battery.c have been adjusted to reflect that. When drivers hooks into the API, the API calls add_battery() for each battery in the system that passes it a acpi_battery struct. Then, the drivers can use device_create_file() to create new sysfs attributes with that struct and identify the batteries for per-battery attributes. Tested-by: Kevin Locke <kevin@xxxxxxxxxxxxxxx> Tested-by: Christoph Böhmwalder <christoph@xxxxxxxxxxxxxx> Signed-off-by: Ognjen Galic <smclt30p@xxxxxxxxx> --- drivers/acpi/ac.c | 2 +- drivers/acpi/battery.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++++- drivers/acpi/battery.h | 11 ---- drivers/acpi/sbs.c | 2 +- include/acpi/battery.h | 21 ++++++++ 5 files changed, 160 insertions(+), 15 deletions(-) delete mode 100644 drivers/acpi/battery.h create mode 100644 include/acpi/battery.h diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c index 47a7ed5..2d8de2f 100644 --- a/drivers/acpi/ac.c +++ b/drivers/acpi/ac.c @@ -33,7 +33,7 @@ #include <linux/platform_device.h> #include <linux/power_supply.h> #include <linux/acpi.h> -#include "battery.h" +#include <acpi/battery.h> #define PREFIX "ACPI: " diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index 13e7b56..2951d07 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -30,6 +30,7 @@ #include <linux/dmi.h> #include <linux/delay.h> #include <linux/slab.h> +#include <linux/list.h> #include <linux/suspend.h> #include <asm/unaligned.h> @@ -42,7 +43,7 @@ #include <linux/acpi.h> #include <linux/power_supply.h> -#include "battery.h" +#include <acpi/battery.h> #define PREFIX "ACPI: " @@ -124,6 +125,7 @@ struct acpi_battery { struct power_supply_desc bat_desc; struct acpi_device *device; struct notifier_block pm_nb; + struct list_head list; unsigned long update_time; int revision; int rate_now; @@ -626,6 +628,137 @@ static const struct device_attribute alarm_attr = { .store = acpi_battery_alarm_store, }; +/* + * The Battery Hooking API + * + * This API is used inside other drivers that need to expose + * platform-specific behaviour within the generic driver in a + * generic way. + * + */ + +LIST_HEAD(acpi_battery_list); +LIST_HEAD(battery_hook_list); + +void battery_hook_unregister(struct acpi_battery_hook *hook) +{ + + struct list_head *position; + struct acpi_battery *battery; + + /* + * In order to remove a hook, we first need to + * de-register all the batteries that are registered. + */ + + list_for_each(position, &acpi_battery_list) { + battery = list_entry(position, struct acpi_battery, list); + hook->remove_battery(battery->bat); + } + + /* Then, just remove the hook */ + + list_del(&hook->list); + pr_info("battery: extension unregistered: %s\n", hook->name); + +} +EXPORT_SYMBOL_GPL(battery_hook_unregister); + +void battery_hook_register(struct acpi_battery_hook *hook) +{ + struct list_head *position; + struct acpi_battery *battery; + + INIT_LIST_HEAD(&hook->list); + list_add(&hook->list, &battery_hook_list); + + /* + * Now that the driver is registered, we need + * to notify the hook that a battery is available + * for each battery, so that the driver may add + * its attributes. + */ + list_for_each(position, &acpi_battery_list) { + battery = list_entry(position, struct acpi_battery, list); + if (hook->add_battery(battery->bat)) { + + /* + * If a add-battery returns non-zero, + * the registration of the extension has failed, + * we will unload it. + */ + pr_err("battery: extension failed to load: %s", + hook->name); + battery_hook_unregister(hook); + return; + + } + } + + pr_info("battery: new extension: %s\n", hook->name); + +} +EXPORT_SYMBOL_GPL(battery_hook_register); + +static void battery_hook_add_battery(struct acpi_battery *battery) +{ + + /* + * This function gets called right after the battery sysfs + * attributes have been added, so that the drivers that + * define custom sysfs attributes can add their own. + */ + + struct list_head *position; + struct acpi_battery_hook *hook_node; + + INIT_LIST_HEAD(&battery->list); + list_add(&battery->list, &acpi_battery_list); + + /* + * Since we added a new battery to the list, we need to + * iterate over the hooks and call add_battery for each + * hook that was registered. This usually happens + * when a battery gets hotplugged or initialized + * during the battery module initialization. + */ + + list_for_each(position, &battery_hook_list) { + hook_node = list_entry(position, struct acpi_battery_hook, list); + if (hook_node->add_battery(battery->bat)) { + + /* + * The notification of the extensions has failed, to + * prevent further errors we will unload the extension. + */ + battery_hook_unregister(hook_node); + pr_err("battery: error in extension, unloading: %s", + hook_node->name); + } + } + +} + +static void battery_hook_remove_battery(struct acpi_battery *battery) +{ + struct list_head *position; + struct acpi_battery_hook *hook; + + /* + * Before removing the hook, we need to remove all + * custom attributes from the battery. + */ + list_for_each(position, &battery_hook_list) { + hook = list_entry(position, struct acpi_battery_hook, list); + hook->remove_battery(battery->bat); + } + + /* Then, just remove the battery from the list */ + + list_del(&battery->list); + +} + static int sysfs_add_battery(struct acpi_battery *battery) { struct power_supply_config psy_cfg = { .drv_data = battery, }; @@ -647,6 +780,8 @@ static int sysfs_add_battery(struct acpi_battery *battery) battery->bat = power_supply_register_no_ws(&battery->device->dev, &battery->bat_desc, &psy_cfg); + battery_hook_add_battery(battery); + if (IS_ERR(battery->bat)) { int result = PTR_ERR(battery->bat); @@ -663,7 +798,7 @@ static void sysfs_remove_battery(struct acpi_battery *battery) mutex_unlock(&battery->sysfs_lock); return; } - + battery_hook_remove_battery(battery); device_remove_file(&battery->bat->dev, &alarm_attr); power_supply_unregister(battery->bat); battery->bat = NULL; diff --git a/drivers/acpi/battery.h b/drivers/acpi/battery.h deleted file mode 100644 index 225f493..0000000 --- a/drivers/acpi/battery.h +++ /dev/null @@ -1,11 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef __ACPI_BATTERY_H -#define __ACPI_BATTERY_H - -#define ACPI_BATTERY_CLASS "battery" - -#define ACPI_BATTERY_NOTIFY_STATUS 0x80 -#define ACPI_BATTERY_NOTIFY_INFO 0x81 -#define ACPI_BATTERY_NOTIFY_THRESHOLD 0x82 - -#endif diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c index a2428e9..295b592 100644 --- a/drivers/acpi/sbs.c +++ b/drivers/acpi/sbs.c @@ -32,9 +32,9 @@ #include <linux/delay.h> #include <linux/power_supply.h> #include <linux/platform_data/x86/apple.h> +#include <acpi/battery.h> #include "sbshc.h" -#include "battery.h" #define PREFIX "ACPI: " diff --git a/include/acpi/battery.h b/include/acpi/battery.h new file mode 100644 index 0000000..5d8f5d9 --- /dev/null +++ b/include/acpi/battery.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ACPI_BATTERY_H +#define __ACPI_BATTERY_H + +#define ACPI_BATTERY_CLASS "battery" + +#define ACPI_BATTERY_NOTIFY_STATUS 0x80 +#define ACPI_BATTERY_NOTIFY_INFO 0x81 +#define ACPI_BATTERY_NOTIFY_THRESHOLD 0x82 + +struct acpi_battery_hook { + const char *name; + int (*add_battery)(struct power_supply *battery); + int (*remove_battery)(struct power_supply *battery); + struct list_head list; +}; + +void battery_hook_register(struct acpi_battery_hook *hook); +void battery_hook_unregister(struct acpi_battery_hook *hook); + +#endif -- 2.7.4